Tengri controlled Thunder and Lightning, who punished malicious forces. Thunder was the angry voice of Tengri and lightning his heavenly arrows, which struck malicious spirits. A house struck by lightning was believed to have deserved Tengri’s anger and was not extinguished until it had completely burned down. Nobody would come near it and no new house was built there, for it was believed that it would not sustain happiness. The beliefs of the ancient Turks prohibited the use of trees struck by a lightning, not only for construction, but also as fuel. However, splinters from such a tree were used as medicines and the sick fumigated with coals from it. The Turks noticed that lightning did not strike sacred birches, because they had links to the Sky. A man killed by lightning was considered ‘sacred’. Sacrifices were offered to spirits, in places struck by lightning.